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  • Density is the amount of matter contained by a body.
  • Density is defined as mass per unit volume of the substance.
  • It is denoted by, 'd' or 'ρ' (rho).

Do you Know

  • The SI unit of density is kg/m^3.
  • Its CGS unit of density is g/cm^3

Density = Mass/Volume
and by this formula, we can get the following formulae:

  1. Mass = Density * Volume
  2. Volume= Mass/Density

Density of Common Substances

Density of Mercury (Hg) = 13.6 g/cm^3
Density of Water = 1 g/cm^3
Density of Air = 0.00129 g/cm^3
Density of Ice=  0.9 g/cm^3

Do You Know

  • 2 substances always get separated into different layers according to their densities.
  • The lighter substance always floats on the heavier substance. You may have noticed that:

  1. Oil floats on water this is because the density of oil is less than the density if water
  2. Ice floats on water this is because the density of ice is less than water